Inner-vaginal Ultrasound

I’ve been spotting for almost a week now, HCG levels are rising but severely slow (no more than 40 every two days) so they brought me in for a inner-vaginal ultrasound today and said it’s too early to see anything but possibly a threatened miscarriage. A few hours after my ultrasound I got bad period-like cramps and I’m filling a pad every hour or two... coincidental the miscarriage is happening now or is it normal to bleed that much after having the ultrasound done?